AusTraits, a curated plant trait database for the Australian flora

We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge

Effects of high salinity from desalination brine on growth, photosynthesis, water relations and osmolyte concentrations of seagrass Posidonia australis

Highly saline brines from desalination plants expose seagrass communities to salt stress. We examined effects of raised salinity (46 and 54psu) compared with seawater controls (37psu) over 6weeks on the seagrass, Posidonia australis, growing in tanks with the aim of separating effects of salinity from other potentially deleterious components of brine and determining appropriate bioindicators. Plants survived exposures of 2-4weeks at 54psu, the maximum salinity of brine released from a nearby desalination plant. Salinity significantly reduced maximum quantum yield of PSII (chlorophyll a fluorescence emissions). Leaf water potential (Ψw) and osmotic potential (Ψπ) were more negative at increased salinity, while turgor pressure (Ψp) was unaffected. Leaf concentrations of K(+) and Ca(2+) decreased, whereas concentrations of sugars (mainly sucrose) and amino acids increased. We recommend leaf osmolarity, ion, sugar and amino acid concentrations as bioindicators for salinity effects, associated with brine released in desalination plant outfalls

Pattern of solutes accumulated during leaf osmotic adjustment as related to duration of water deficit for wheat at the reproductive stage

This study examined expression of osmotic adjustment (OA) and accumulation of solutes in wheat (Triticum aestivum L) leaves in response to water deficit (WD) imposed at the reproductive stage. Two contrasting cultivars, Hartog and Sunco (putatively high and low in OA capacity, respectively), were grown in deep (viz. 80 cm) pots in a controlled environment. In a sandy substrate, leaf OA was 5-times greater in Hartog compared with Sunco. At 21 d of WD treatment, K(+) only accounted for 12% of OA in Hartog and 48% in Sunco with less OA (i.e. tissue K(+) led to different proportions owing to different magnitudes of OA). Glycinebetaine and proline also increased under WD, but these were not significant osmotica on a whole tissue basis. Hartog accumulated dry matter faster than Sunco under WD, and this was consistent with greater water extraction by Hartog than by Sunco. In a second experiment on Hartog, with loam added to the sand to increase water-holding capacity and thus enable a longer draw-down period, leaf OA increased to 0.37 MPa at 37 d of withholding water. K(+) increased up to 16 d of drying and then decreased towards 37 d. Glycinebetaine, proline, glucose and fructose all increased during the draw-down period, although with different dynamics: e.g. glycinebetaine increased linearly whereas glucose showed an exponential increase. By contrast, sucrose declined. K(+) was the major contributor to OA (viz. 54%) up to 30 d of drying, whereas glycinebetaine, proline and glucose were major contributors later (at d 37 these organic solutes each accounted for 19, 21 and 21% of OA). Thus, the various solutes that contributed to leaf OA in wheat cv. Hartog accumulated at different times as WD developed. (C) 2011 Elsevier Masson SAS. All rights reserved

Unique infection structures produced by Pseudocercosporella capsellae on oilseed crops Brassica carinata, B. juncea and B. napus in Western Australia

White leaf spot disease (Pseudocercosporella capsellae) is widespread across oilseed, vegetable and forage brassicas. Light (LM) and scanning electron (SEM) microscope studies were undertaken to investigate host–pathogen interactions on cotyledons of resistant and susceptible Brassica carinata, B. juncea and B. napus. Under LM, unique brown structures were present, particularly on susceptible genotypes, in two morphologically distinct forms: first, as thread-like structures within cortical tissue by 24 h post-inoculation (hpi) and secondly, as brown ropy strand structures either within cortical tissues (internal ropy strands), or extruded out through stomatal pores (ropy strand extrusions). Under LM, these brown structures were most prevalent in highly susceptible B. juncea ‘Vardan’ that had both a high incidence within cortical tissue (70%) and of ropy strand extrusions (73%), as did susceptible B. napus ‘Trilogy’ within cortical tissue (60%). Under SEM, both these genotypes showed thread-like structures smaller than hyphae forming highly branched networks and ropy strand-like structures. While there were fewer brown structures in susceptible B. carinata UWA #012 (35%), fine, thread-like structures forming networks were again prominent (SEM). In contrast, for resistant genotypes, brown structures (LM) were of very low frequency or absent; only 5% in resistant B. juncea ‘Dune’ and none in resistant B. napus ‘Hyola 42’ or highly resistant B. carinata ATC94129P. Under SEM, fine, threadlike structures were present in the resistant B. juncea ‘Dune’ and B. napus ‘Hyola 42’. Liquid chromatographic analyses of brown structures revealed that both internal ropy strands within cortical tissues and ropy strand extrusions contained the mycotoxin cercosporin

Poor regulation of phosphorus uptake and rhizosphere carboxylates in three phosphorus-hyperaccumulating species of Ptilotus

Background and aims Ptilotus polystachyus occurs in phosphorus (P) – poor soils, but can hyperaccumulate P without toxicity. We examined, in P-poor soils, P accumulation and rhizosphere carboxylates for three Ptilotus species, and carboxylate adsorption and associated P release. Methods Ptilotus spp. macrocephalus, nobilis and polystachyus were grown in two soils at 40, 100 and 400 mg P kg−1 soil as KH2PO4. After 6 weeks, dry weight (DW), tissue nutrients and rhizosphere carboxylates were determined. Citrate, malate and oxalate adsorption, and associated P release, was investigated in three soils. Results For all species, shoot DW and carboxylate amount were little affected by increasing P, while green leaves reached ~ 45–60 mg P g−1 DW: tissue P and carbon were negatively correlated. Oxalate was the dominant carboxylate and a large effect of soil type differed with unit (μmol g−1 root DW or rhizosphere soil DW, μmol plant−1). Adsorption was highest for oxalate, but differed with soil type; Freundlich and Langmuir functions generally fitted well. Citrate was the most effective for P release, followed by oxalate. Conclusions Inability to down-regulate P uptake and rhizosphere carboxylates with increasing P may be characteristic of Ptilotus. The role of these traits in adaptation to P-poor soils merits further investigation